(1) Field of the Invention
This invention relates to a liquid crystal display (LCD) panel, and more particularly to a wide viewing angle LCD panel.
(2) Description of the Related Art
Attending with the improvement of thin film transistor (TFT) fabrication technology, LCD with the advantages of slim size, low power consumption, and low radiation emission, has become popular among various electronic devices, such as personal digital assistants (PDA), notebooks (NB), digital cameras (DC), digital videos (DV), cell phone, etc. However, the viewing angle of LCD at present is usually limited due to the optical behavior of liquid crystal (LC) layer with respect to light beams at various tilt angles.
Implementations for improving viewing angle of LCD are taught in some patents, see, e.g., American patent, U.S. Pat. No. 5,410,422, “GRAY SCALE LIQUID CRYSTAL DISPLAY HAVING A WIDE VIEWING ANGLE”. FIG. 1 describes the method taught in the patent, to interpose a birefringence compensator 110 between two linear polarizers 112,114. Light beam traveling through the LC layer 116 with a large tilt angle is usually engaged with phase retardation different from the light beam traveling normal to the LCD panel. The disclosed birefringence compensator 110 characterized with a negative phase retardation to compensate the phase retardation difference so as to increase viewing angle.
It is understood that the birefringence compensator 110 can be adapted to various LC molecule types, e.g., vertical aligned (VA) LC molecules, twisted nematic (TN) LC molecules, in-plane switch (IPS) LC molecules, etc. by properly compensating the phase retardation difference. However, the birefringence compensator 110 increases the thickness and the weight of the LCD panel, which leads to an important issue of increasing viewing angle without the benefit of birefringence compensator.